/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.validation;

import java.beans.PropertyEditor;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.ConfigurablePropertyAccessor;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyAccessException;
import org.springframework.beans.PropertyAccessorUtils;
import org.springframework.beans.PropertyBatchUpdateException;
import org.springframework.beans.PropertyEditorRegistry;
import org.springframework.beans.PropertyValue;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.SimpleTypeConverter;
import org.springframework.beans.TypeConverter;
import org.springframework.beans.TypeMismatchException;
import org.springframework.core.MethodParameter;
import org.springframework.core.convert.ConversionService;
import org.springframework.format.Formatter;
import org.springframework.format.support.FormatterPropertyEditorAdapter;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.PatternMatchUtils;
import org.springframework.util.StringUtils;

/**
 * Binder that allows for setting property values onto a target object,
 * including support for validation and binding result analysis.
 * The binding process can be customized through specifying allowed fields,
 * required fields, custom editors, etc.
 *
 * <p>Note that there are potential security implications in failing to set an array
 * of allowed fields. In the case of HTTP form POST data for example, malicious clients
 * can attempt to subvert an application by supplying values for fields or properties
 * that do not exist on the form. In some cases this could lead to illegal data being
 * set on command objects <i>or their nested objects</i>. For this reason, it is
 * <b>highly recommended to specify the {@link #setAllowedFields allowedFields} property</b>
 * on the DataBinder.
 *
 * <p>The binding results can be examined via the {@link BindingResult} interface,
 * extending the {@link Errors} interface: see the {@link #getBindingResult()} method.
 * Missing fields and property access exceptions will be converted to {@link FieldError FieldErrors},
 * collected in the Errors instance, using the following error codes:
 *
 * <ul>
 * <li>Missing field error: "required"
 * <li>Type mismatch error: "typeMismatch"
 * <li>Method invocation error: "methodInvocation"
 * </ul>
 *
 * <p>By default, binding errors get resolved through the {@link BindingErrorProcessor}
 * strategy, processing for missing fields and property access exceptions: see the
 * {@link #setBindingErrorProcessor} method. You can override the default strategy
 * if needed, for example to generate different error codes.
 *
 * <p>Custom validation errors can be added afterwards. You will typically want to resolve
 * such error codes into proper user-visible error messages; this can be achieved through
 * resolving each error via a {@link org.springframework.context.MessageSource}, which is
 * able to resolve an {@link ObjectError}/{@link FieldError} through its
 * {@link org.springframework.context.MessageSource#getMessage(org.springframework.context.MessageSourceResolvable, java.util.Locale)}
 * method. The list of message codes can be customized through the {@link MessageCodesResolver}
 * strategy: see the {@link #setMessageCodesResolver} method. {@link DefaultMessageCodesResolver}'s
 * javadoc states details on the default resolution rules.
 *
 * <p>This generic data binder can be used in any kind of environment.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @author Stephane Nicoll
 * @author Kazuki Shimizu
 * @see #setAllowedFields
 * @see #setRequiredFields
 * @see #registerCustomEditor
 * @see #setMessageCodesResolver
 * @see #setBindingErrorProcessor
 * @see #bind
 * @see #getBindingResult
 * @see DefaultMessageCodesResolver
 * @see DefaultBindingErrorProcessor
 * @see org.springframework.context.MessageSource
 */
public class DataBinder implements PropertyEditorRegistry, TypeConverter {

    /**
     * Default object name used for binding: "target"
     */
    public static final String DEFAULT_OBJECT_NAME = "target";

    /**
     * Default limit for array and collection growing: 256
     */
    public static final int DEFAULT_AUTO_GROW_COLLECTION_LIMIT = 256;


    /**
     * We'll create a lot of DataBinder instances: Let's use a static logger.
     */
    protected static final Log logger = LogFactory.getLog(DataBinder.class);

    @Nullable
    private final Object target;

    private final String objectName;

    @Nullable
    private AbstractPropertyBindingResult bindingResult;

    @Nullable
    private SimpleTypeConverter typeConverter;

    private boolean ignoreUnknownFields = true;

    private boolean ignoreInvalidFields = false;

    private boolean autoGrowNestedPaths = true;

    private int autoGrowCollectionLimit = DEFAULT_AUTO_GROW_COLLECTION_LIMIT;

    @Nullable
    private String[] allowedFields;

    @Nullable
    private String[] disallowedFields;

    @Nullable
    private String[] requiredFields;

    @Nullable
    private ConversionService conversionService;

    @Nullable
    private MessageCodesResolver messageCodesResolver;

    private BindingErrorProcessor bindingErrorProcessor = new DefaultBindingErrorProcessor();

    private final List<Validator> validators = new ArrayList<>();


    /**
     * Create a new DataBinder instance, with default object name.
     *
     * @param target the target object to bind onto (or {@code null}
     *               if the binder is just used to convert a plain parameter value)
     * @see #DEFAULT_OBJECT_NAME
     */
    public DataBinder(@Nullable Object target) {
        this(target, DEFAULT_OBJECT_NAME);
    }

    /**
     * Create a new DataBinder instance.
     *
     * @param target     the target object to bind onto (or {@code null}
     *                   if the binder is just used to convert a plain parameter value)
     * @param objectName the name of the target object
     */
    public DataBinder(@Nullable Object target, String objectName) {
        this.target = ObjectUtils.unwrapOptional(target);
        this.objectName = objectName;
    }


    /**
     * Return the wrapped target object.
     */
    @Nullable
    public Object getTarget() {
        return this.target;
    }

    /**
     * Return the name of the bound object.
     */
    public String getObjectName() {
        return this.objectName;
    }

    /**
     * Set whether this binder should attempt to "auto-grow" a nested path that contains a null value.
     * <p>If "true", a null path location will be populated with a default object value and traversed
     * instead of resulting in an exception. This flag also enables auto-growth of collection elements
     * when accessing an out-of-bounds index.
     * <p>Default is "true" on a standard DataBinder. Note that since Spring 4.1 this feature is supported
     * for bean property access (DataBinder's default mode) and field access.
     *
     * @see #initBeanPropertyAccess()
     * @see org.springframework.beans.BeanWrapper#setAutoGrowNestedPaths
     */
    public void setAutoGrowNestedPaths(boolean autoGrowNestedPaths) {
        Assert.state(this.bindingResult == null,
                "DataBinder is already initialized - call setAutoGrowNestedPaths before other configuration methods");
        this.autoGrowNestedPaths = autoGrowNestedPaths;
    }

    /**
     * Return whether "auto-growing" of nested paths has been activated.
     */
    public boolean isAutoGrowNestedPaths() {
        return this.autoGrowNestedPaths;
    }

    /**
     * Specify the limit for array and collection auto-growing.
     * <p>Default is 256, preventing OutOfMemoryErrors in case of large indexes.
     * Raise this limit if your auto-growing needs are unusually high.
     *
     * @see #initBeanPropertyAccess()
     * @see org.springframework.beans.BeanWrapper#setAutoGrowCollectionLimit
     */
    public void setAutoGrowCollectionLimit(int autoGrowCollectionLimit) {
        Assert.state(this.bindingResult == null,
                "DataBinder is already initialized - call setAutoGrowCollectionLimit before other configuration methods");
        this.autoGrowCollectionLimit = autoGrowCollectionLimit;
    }

    /**
     * Return the current limit for array and collection auto-growing.
     */
    public int getAutoGrowCollectionLimit() {
        return this.autoGrowCollectionLimit;
    }

    /**
     * Initialize standard JavaBean property access for this DataBinder.
     * <p>This is the default; an explicit call just leads to eager initialization.
     *
     * @see #initDirectFieldAccess()
     * @see #createBeanPropertyBindingResult()
     */
    public void initBeanPropertyAccess() {
        Assert.state(this.bindingResult == null,
                "DataBinder is already initialized - call initBeanPropertyAccess before other configuration methods");
        this.bindingResult = createBeanPropertyBindingResult();
    }

    /**
     * Create the {@link AbstractPropertyBindingResult} instance using standard
     * JavaBean property access.
     *
     * @since 4.2.1
     */
    protected AbstractPropertyBindingResult createBeanPropertyBindingResult() {
        BeanPropertyBindingResult result = new BeanPropertyBindingResult(getTarget(),
                getObjectName(), isAutoGrowNestedPaths(), getAutoGrowCollectionLimit());

        if (this.conversionService != null) {
            result.initConversion(this.conversionService);
        }
        if (this.messageCodesResolver != null) {
            result.setMessageCodesResolver(this.messageCodesResolver);
        }

        return result;
    }

    /**
     * Initialize direct field access for this DataBinder,
     * as alternative to the default bean property access.
     *
     * @see #initBeanPropertyAccess()
     * @see #createDirectFieldBindingResult()
     */
    public void initDirectFieldAccess() {
        Assert.state(this.bindingResult == null,
                "DataBinder is already initialized - call initDirectFieldAccess before other configuration methods");
        this.bindingResult = createDirectFieldBindingResult();
    }

    /**
     * Create the {@link AbstractPropertyBindingResult} instance using direct
     * field access.
     *
     * @since 4.2.1
     */
    protected AbstractPropertyBindingResult createDirectFieldBindingResult() {
        DirectFieldBindingResult result = new DirectFieldBindingResult(getTarget(),
                getObjectName(), isAutoGrowNestedPaths());

        if (this.conversionService != null) {
            result.initConversion(this.conversionService);
        }
        if (this.messageCodesResolver != null) {
            result.setMessageCodesResolver(this.messageCodesResolver);
        }

        return result;
    }

    /**
     * Return the internal BindingResult held by this DataBinder,
     * as an AbstractPropertyBindingResult.
     */
    protected AbstractPropertyBindingResult getInternalBindingResult() {
        if (this.bindingResult == null) {
            initBeanPropertyAccess();
        }
        return this.bindingResult;
    }

    /**
     * Return the underlying PropertyAccessor of this binder's BindingResult.
     */
    protected ConfigurablePropertyAccessor getPropertyAccessor() {
        return getInternalBindingResult().getPropertyAccessor();
    }

    /**
     * Return this binder's underlying SimpleTypeConverter.
     */
    protected SimpleTypeConverter getSimpleTypeConverter() {
        if (this.typeConverter == null) {
            this.typeConverter = new SimpleTypeConverter();
            if (this.conversionService != null) {
                this.typeConverter.setConversionService(this.conversionService);
            }
        }
        return this.typeConverter;
    }

    /**
     * Return the underlying TypeConverter of this binder's BindingResult.
     */
    protected PropertyEditorRegistry getPropertyEditorRegistry() {
        if (getTarget() != null) {
            return getInternalBindingResult().getPropertyAccessor();
        } else {
            return getSimpleTypeConverter();
        }
    }

    /**
     * Return the underlying TypeConverter of this binder's BindingResult.
     */
    protected TypeConverter getTypeConverter() {
        if (getTarget() != null) {
            return getInternalBindingResult().getPropertyAccessor();
        } else {
            return getSimpleTypeConverter();
        }
    }

    /**
     * Return the BindingResult instance created by this DataBinder.
     * This allows for convenient access to the binding results after
     * a bind operation.
     *
     * @return the BindingResult instance, to be treated as BindingResult
     * or as Errors instance (Errors is a super-interface of BindingResult)
     * @see Errors
     * @see #bind
     */
    public BindingResult getBindingResult() {
        return getInternalBindingResult();
    }


    /**
     * Set whether to ignore unknown fields, that is, whether to ignore bind
     * parameters that do not have corresponding fields in the target object.
     * <p>Default is "true". Turn this off to enforce that all bind parameters
     * must have a matching field in the target object.
     * <p>Note that this setting only applies to <i>binding</i> operations
     * on this DataBinder, not to <i>retrieving</i> values via its
     * {@link #getBindingResult() BindingResult}.
     *
     * @see #bind
     */
    public void setIgnoreUnknownFields(boolean ignoreUnknownFields) {
        this.ignoreUnknownFields = ignoreUnknownFields;
    }

    /**
     * Return whether to ignore unknown fields when binding.
     */
    public boolean isIgnoreUnknownFields() {
        return this.ignoreUnknownFields;
    }

    /**
     * Set whether to ignore invalid fields, that is, whether to ignore bind
     * parameters that have corresponding fields in the target object which are
     * not accessible (for example because of null values in the nested path).
     * <p>Default is "false". Turn this on to ignore bind parameters for
     * nested objects in non-existing parts of the target object graph.
     * <p>Note that this setting only applies to <i>binding</i> operations
     * on this DataBinder, not to <i>retrieving</i> values via its
     * {@link #getBindingResult() BindingResult}.
     *
     * @see #bind
     */
    public void setIgnoreInvalidFields(boolean ignoreInvalidFields) {
        this.ignoreInvalidFields = ignoreInvalidFields;
    }

    /**
     * Return whether to ignore invalid fields when binding.
     */
    public boolean isIgnoreInvalidFields() {
        return this.ignoreInvalidFields;
    }

    /**
     * Register fields that should be allowed for binding. Default is all
     * fields. Restrict this for example to avoid unwanted modifications
     * by malicious users when binding HTTP request parameters.
     * <p>Supports "xxx*", "*xxx" and "*xxx*" patterns. More sophisticated matching
     * can be implemented by overriding the {@code isAllowed} method.
     * <p>Alternatively, specify a list of <i>disallowed</i> fields.
     *
     * @param allowedFields array of field names
     * @see #setDisallowedFields
     * @see #isAllowed(String)
     */
    public void setAllowedFields(@Nullable String... allowedFields) {
        this.allowedFields = PropertyAccessorUtils.canonicalPropertyNames(allowedFields);
    }

    /**
     * Return the fields that should be allowed for binding.
     *
     * @return array of field names
     */
    @Nullable
    public String[] getAllowedFields() {
        return this.allowedFields;
    }

    /**
     * Register fields that should <i>not</i> be allowed for binding. Default is none.
     * Mark fields as disallowed for example to avoid unwanted modifications
     * by malicious users when binding HTTP request parameters.
     * <p>Supports "xxx*", "*xxx" and "*xxx*" patterns. More sophisticated matching
     * can be implemented by overriding the {@code isAllowed} method.
     * <p>Alternatively, specify a list of <i>allowed</i> fields.
     *
     * @param disallowedFields array of field names
     * @see #setAllowedFields
     * @see #isAllowed(String)
     */
    public void setDisallowedFields(@Nullable String... disallowedFields) {
        this.disallowedFields = PropertyAccessorUtils.canonicalPropertyNames(disallowedFields);
    }

    /**
     * Return the fields that should <i>not</i> be allowed for binding.
     *
     * @return array of field names
     */
    @Nullable
    public String[] getDisallowedFields() {
        return this.disallowedFields;
    }

    /**
     * Register fields that are required for each binding process.
     * <p>If one of the specified fields is not contained in the list of
     * incoming property values, a corresponding "missing field" error
     * will be created, with error code "required" (by the default
     * binding error processor).
     *
     * @param requiredFields array of field names
     * @see #setBindingErrorProcessor
     * @see DefaultBindingErrorProcessor#MISSING_FIELD_ERROR_CODE
     */
    public void setRequiredFields(@Nullable String... requiredFields) {
        this.requiredFields = PropertyAccessorUtils.canonicalPropertyNames(requiredFields);
        if (logger.isDebugEnabled()) {
            logger.debug("DataBinder requires binding of required fields [" +
                    StringUtils.arrayToCommaDelimitedString(requiredFields) + "]");
        }
    }

    /**
     * Return the fields that are required for each binding process.
     *
     * @return array of field names
     */
    @Nullable
    public String[] getRequiredFields() {
        return this.requiredFields;
    }

    /**
     * Set the strategy to use for resolving errors into message codes.
     * Applies the given strategy to the underlying errors holder.
     * <p>Default is a DefaultMessageCodesResolver.
     *
     * @see BeanPropertyBindingResult#setMessageCodesResolver
     * @see DefaultMessageCodesResolver
     */
    public void setMessageCodesResolver(@Nullable MessageCodesResolver messageCodesResolver) {
        Assert.state(this.messageCodesResolver == null, "DataBinder is already initialized with MessageCodesResolver");
        this.messageCodesResolver = messageCodesResolver;
        if (this.bindingResult != null && messageCodesResolver != null) {
            this.bindingResult.setMessageCodesResolver(messageCodesResolver);
        }
    }

    /**
     * Set the strategy to use for processing binding errors, that is,
     * required field errors and {@code PropertyAccessException}s.
     * <p>Default is a DefaultBindingErrorProcessor.
     *
     * @see DefaultBindingErrorProcessor
     */
    public void setBindingErrorProcessor(BindingErrorProcessor bindingErrorProcessor) {
        Assert.notNull(bindingErrorProcessor, "BindingErrorProcessor must not be null");
        this.bindingErrorProcessor = bindingErrorProcessor;
    }

    /**
     * Return the strategy for processing binding errors.
     */
    public BindingErrorProcessor getBindingErrorProcessor() {
        return this.bindingErrorProcessor;
    }

    /**
     * Set the Validator to apply after each binding step.
     *
     * @see #addValidators(Validator...)
     * @see #replaceValidators(Validator...)
     */
    public void setValidator(@Nullable Validator validator) {
        assertValidators(validator);
        this.validators.clear();
        if (validator != null) {
            this.validators.add(validator);
        }
    }

    private void assertValidators(Validator... validators) {
        Object target = getTarget();
        for (Validator validator : validators) {
            if (validator != null && (target != null && !validator.supports(target.getClass()))) {
                throw new IllegalStateException("Invalid target for Validator [" + validator + "]: " + target);
            }
        }
    }

    /**
     * Add Validators to apply after each binding step.
     *
     * @see #setValidator(Validator)
     * @see #replaceValidators(Validator...)
     */
    public void addValidators(Validator... validators) {
        assertValidators(validators);
        this.validators.addAll(Arrays.asList(validators));
    }

    /**
     * Replace the Validators to apply after each binding step.
     *
     * @see #setValidator(Validator)
     * @see #addValidators(Validator...)
     */
    public void replaceValidators(Validator... validators) {
        assertValidators(validators);
        this.validators.clear();
        this.validators.addAll(Arrays.asList(validators));
    }

    /**
     * Return the primary Validator to apply after each binding step, if any.
     */
    @Nullable
    public Validator getValidator() {
        return (!this.validators.isEmpty() ? this.validators.get(0) : null);
    }

    /**
     * Return the Validators to apply after data binding.
     */
    public List<Validator> getValidators() {
        return Collections.unmodifiableList(this.validators);
    }


    //---------------------------------------------------------------------
    // Implementation of PropertyEditorRegistry/TypeConverter interface
    //---------------------------------------------------------------------

    /**
     * Specify a Spring 3.0 ConversionService to use for converting
     * property values, as an alternative to JavaBeans PropertyEditors.
     */
    public void setConversionService(@Nullable ConversionService conversionService) {
        Assert.state(this.conversionService == null, "DataBinder is already initialized with ConversionService");
        this.conversionService = conversionService;
        if (this.bindingResult != null && conversionService != null) {
            this.bindingResult.initConversion(conversionService);
        }
    }

    /**
     * Return the associated ConversionService, if any.
     */
    @Nullable
    public ConversionService getConversionService() {
        return this.conversionService;
    }

    /**
     * Add a custom formatter, applying it to all fields matching the
     * {@link Formatter}-declared type.
     * <p>Registers a corresponding {@link PropertyEditor} adapter underneath the covers.
     *
     * @param formatter the formatter to add, generically declared for a specific type
     * @see #registerCustomEditor(Class, PropertyEditor)
     * @since 4.2
     */
    public void addCustomFormatter(Formatter<?> formatter) {
        FormatterPropertyEditorAdapter adapter = new FormatterPropertyEditorAdapter(formatter);
        getPropertyEditorRegistry().registerCustomEditor(adapter.getFieldType(), adapter);
    }

    /**
     * Add a custom formatter for the field type specified in {@link Formatter} class,
     * applying it to the specified fields only, if any, or otherwise to all fields.
     * <p>Registers a corresponding {@link PropertyEditor} adapter underneath the covers.
     *
     * @param formatter the formatter to add, generically declared for a specific type
     * @param fields    the fields to apply the formatter to, or none if to be applied to all
     * @see #registerCustomEditor(Class, String, PropertyEditor)
     * @since 4.2
     */
    public void addCustomFormatter(Formatter<?> formatter, String... fields) {
        FormatterPropertyEditorAdapter adapter = new FormatterPropertyEditorAdapter(formatter);
        Class<?> fieldType = adapter.getFieldType();
        if (ObjectUtils.isEmpty(fields)) {
            getPropertyEditorRegistry().registerCustomEditor(fieldType, adapter);
        } else {
            for (String field : fields) {
                getPropertyEditorRegistry().registerCustomEditor(fieldType, field, adapter);
            }
        }
    }

    /**
     * Add a custom formatter, applying it to the specified field types only, if any,
     * or otherwise to all fields matching the {@link Formatter}-declared type.
     * <p>Registers a corresponding {@link PropertyEditor} adapter underneath the covers.
     *
     * @param formatter  the formatter to add (does not need to generically declare a
     *                   field type if field types are explicitly specified as parameters)
     * @param fieldTypes the field types to apply the formatter to, or none if to be
     *                   derived from the given {@link Formatter} implementation class
     * @see #registerCustomEditor(Class, PropertyEditor)
     * @since 4.2
     */
    public void addCustomFormatter(Formatter<?> formatter, Class<?>... fieldTypes) {
        FormatterPropertyEditorAdapter adapter = new FormatterPropertyEditorAdapter(formatter);
        if (ObjectUtils.isEmpty(fieldTypes)) {
            getPropertyEditorRegistry().registerCustomEditor(adapter.getFieldType(), adapter);
        } else {
            for (Class<?> fieldType : fieldTypes) {
                getPropertyEditorRegistry().registerCustomEditor(fieldType, adapter);
            }
        }
    }

    @Override
    public void registerCustomEditor(Class<?> requiredType, PropertyEditor propertyEditor) {
        getPropertyEditorRegistry().registerCustomEditor(requiredType, propertyEditor);
    }

    @Override
    public void registerCustomEditor(@Nullable Class<?> requiredType, @Nullable String field, PropertyEditor propertyEditor) {
        getPropertyEditorRegistry().registerCustomEditor(requiredType, field, propertyEditor);
    }

    @Override
    @Nullable
    public PropertyEditor findCustomEditor(@Nullable Class<?> requiredType, @Nullable String propertyPath) {
        return getPropertyEditorRegistry().findCustomEditor(requiredType, propertyPath);
    }

    @Override
    @Nullable
    public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType) throws TypeMismatchException {
        return getTypeConverter().convertIfNecessary(value, requiredType);
    }

    @Override
    @Nullable
    public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType,
                                    @Nullable MethodParameter methodParam) throws TypeMismatchException {

        return getTypeConverter().convertIfNecessary(value, requiredType, methodParam);
    }

    @Override
    @Nullable
    public <T> T convertIfNecessary(@Nullable Object value, @Nullable Class<T> requiredType, @Nullable Field field)
            throws TypeMismatchException {

        return getTypeConverter().convertIfNecessary(value, requiredType, field);
    }


    /**
     * Bind the given property values to this binder's target.
     * <p>This call can create field errors, representing basic binding
     * errors like a required field (code "required"), or type mismatch
     * between value and bean property (code "typeMismatch").
     * <p>Note that the given PropertyValues should be a throwaway instance:
     * For efficiency, it will be modified to just contain allowed fields if it
     * implements the MutablePropertyValues interface; else, an internal mutable
     * copy will be created for this purpose. Pass in a copy of the PropertyValues
     * if you want your original instance to stay unmodified in any case.
     *
     * @param pvs property values to bind
     * @see #doBind(org.springframework.beans.MutablePropertyValues)
     */
    public void bind(PropertyValues pvs) {
        MutablePropertyValues mpvs = (pvs instanceof MutablePropertyValues) ?
                (MutablePropertyValues) pvs : new MutablePropertyValues(pvs);
        doBind(mpvs);
    }

    /**
     * Actual implementation of the binding process, working with the
     * passed-in MutablePropertyValues instance.
     *
     * @param mpvs the property values to bind,
     *             as MutablePropertyValues instance
     * @see #checkAllowedFields
     * @see #checkRequiredFields
     * @see #applyPropertyValues
     */
    protected void doBind(MutablePropertyValues mpvs) {
        checkAllowedFields(mpvs);
        checkRequiredFields(mpvs);
        applyPropertyValues(mpvs);
    }

    /**
     * Check the given property values against the allowed fields,
     * removing values for fields that are not allowed.
     *
     * @param mpvs the property values to be bound (can be modified)
     * @see #getAllowedFields
     * @see #isAllowed(String)
     */
    protected void checkAllowedFields(MutablePropertyValues mpvs) {
        PropertyValue[] pvs = mpvs.getPropertyValues();
        for (PropertyValue pv : pvs) {
            String field = PropertyAccessorUtils.canonicalPropertyName(pv.getName());
            if (!isAllowed(field)) {
                mpvs.removePropertyValue(pv);
                getBindingResult().recordSuppressedField(field);
                if (logger.isDebugEnabled()) {
                    logger.debug("Field [" + field + "] has been removed from PropertyValues " +
                            "and will not be bound, because it has not been found in the list of allowed fields");
                }
            }
        }
    }

    /**
     * Return if the given field is allowed for binding.
     * Invoked for each passed-in property value.
     * <p>The default implementation checks for "xxx*", "*xxx" and "*xxx*" matches,
     * as well as direct equality, in the specified lists of allowed fields and
     * disallowed fields. A field matching a disallowed pattern will not be accepted
     * even if it also happens to match a pattern in the allowed list.
     * <p>Can be overridden in subclasses.
     *
     * @param field the field to check
     * @return if the field is allowed
     * @see #setAllowedFields
     * @see #setDisallowedFields
     * @see org.springframework.util.PatternMatchUtils#simpleMatch(String, String)
     */
    protected boolean isAllowed(String field) {
        String[] allowed = getAllowedFields();
        String[] disallowed = getDisallowedFields();
        return ((ObjectUtils.isEmpty(allowed) || PatternMatchUtils.simpleMatch(allowed, field)) &&
                (ObjectUtils.isEmpty(disallowed) || !PatternMatchUtils.simpleMatch(disallowed, field)));
    }

    /**
     * Check the given property values against the required fields,
     * generating missing field errors where appropriate.
     *
     * @param mpvs the property values to be bound (can be modified)
     * @see #getRequiredFields
     * @see #getBindingErrorProcessor
     * @see BindingErrorProcessor#processMissingFieldError
     */
    protected void checkRequiredFields(MutablePropertyValues mpvs) {
        String[] requiredFields = getRequiredFields();
        if (!ObjectUtils.isEmpty(requiredFields)) {
            Map<String, PropertyValue> propertyValues = new HashMap<>();
            PropertyValue[] pvs = mpvs.getPropertyValues();
            for (PropertyValue pv : pvs) {
                String canonicalName = PropertyAccessorUtils.canonicalPropertyName(pv.getName());
                propertyValues.put(canonicalName, pv);
            }
            for (String field : requiredFields) {
                PropertyValue pv = propertyValues.get(field);
                boolean empty = (pv == null || pv.getValue() == null);
                if (!empty) {
                    if (pv.getValue() instanceof String) {
                        empty = !StringUtils.hasText((String) pv.getValue());
                    } else if (pv.getValue() instanceof String[]) {
                        String[] values = (String[]) pv.getValue();
                        empty = (values.length == 0 || !StringUtils.hasText(values[0]));
                    }
                }
                if (empty) {
                    // Use bind error processor to create FieldError.
                    getBindingErrorProcessor().processMissingFieldError(field, getInternalBindingResult());
                    // Remove property from property values to bind:
                    // It has already caused a field error with a rejected value.
                    if (pv != null) {
                        mpvs.removePropertyValue(pv);
                        propertyValues.remove(field);
                    }
                }
            }
        }
    }

    /**
     * Apply given property values to the target object.
     * <p>Default implementation applies all of the supplied property
     * values as bean property values. By default, unknown fields will
     * be ignored.
     *
     * @param mpvs the property values to be bound (can be modified)
     * @see #getTarget
     * @see #getPropertyAccessor
     * @see #isIgnoreUnknownFields
     * @see #getBindingErrorProcessor
     * @see BindingErrorProcessor#processPropertyAccessException
     */
    protected void applyPropertyValues(MutablePropertyValues mpvs) {
        try {
            // Bind request parameters onto target object.
            getPropertyAccessor().setPropertyValues(mpvs, isIgnoreUnknownFields(), isIgnoreInvalidFields());
        } catch (PropertyBatchUpdateException ex) {
            // Use bind error processor to create FieldErrors.
            for (PropertyAccessException pae : ex.getPropertyAccessExceptions()) {
                getBindingErrorProcessor().processPropertyAccessException(pae, getInternalBindingResult());
            }
        }
    }


    /**
     * Invoke the specified Validators, if any.
     *
     * @see #setValidator(Validator)
     * @see #getBindingResult()
     */
    public void validate() {
        for (Validator validator : this.validators) {
            validator.validate(getTarget(), getBindingResult());
        }
    }

    /**
     * Invoke the specified Validators, if any, with the given validation hints.
     * <p>Note: Validation hints may get ignored by the actual target Validator.
     *
     * @param validationHints one or more hint objects to be passed to a {@link SmartValidator}
     * @see #setValidator(Validator)
     * @see SmartValidator#validate(Object, Errors, Object...)
     */
    public void validate(Object... validationHints) {
        for (Validator validator : getValidators()) {
            if (!ObjectUtils.isEmpty(validationHints) && validator instanceof SmartValidator) {
                ((SmartValidator) validator).validate(getTarget(), getBindingResult(), validationHints);
            } else if (validator != null) {
                validator.validate(getTarget(), getBindingResult());
            }
        }
    }

    /**
     * Close this DataBinder, which may result in throwing
     * a BindException if it encountered any errors.
     *
     * @return the model Map, containing target object and Errors instance
     * @throws BindException if there were any errors in the bind operation
     * @see BindingResult#getModel()
     */
    public Map<?, ?> close() throws BindException {
        if (getBindingResult().hasErrors()) {
            throw new BindException(getBindingResult());
        }
        return getBindingResult().getModel();
    }

}
